Secure semiconductor chip and operating method thereof

ABSTRACT

Disclosed is a secure semiconductor chip. When a physical attack such as a depackaging attack occurs, the semiconductor chip can detect the physical attack. A semiconductor chip according to one embodiment comprises an energy harvesting element inside a package. The energy harvesting element may comprise, for example, an on-chip photodiode. A depackaging attack causes the generation of a voltage of a photodiode, and thus a change in physical state of the packaging can be detected.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Stage Entry of PCT InternationalApplication No. PCT/KR2017/001491, which was filed on Feb. 10, 2017, andwhich claims priority from Korean Patent Application No. 10-2016-0016587filed with the Korean Intellectual Property Office on Feb. 12, 2016, andKorean Patent Application No. 10-2017-0018692 filed with the KoreanIntellectual Property Office on Feb. 10, 2017. The disclosures of theabove patent applications are incorporated herein by reference in theirentirety.

BACKGROUND 1. Technical Field

The present invention relates to a semiconductor chip having increasedsecurity and a method for operating the same, more particularly to thedetection of physical attacks against the semiconductor chip.

2. Description of the Related Art

Various physical attacks and software attacks on semiconductor chipspose a threat against products using SoC (system-on-chip) technology andapplication services based on such products. There are various knownexamples of physical attacks, such as depackaging, circuit deformationusing a FIB (focused ion beam), micro-probing, power analysis, EMA(electromagnetic analysis), fault injection using voltage, frequency, ortemperature alterations, etc.

Techniques for detecting physical attacks and protecting the circuithave been introduced, and the prior art documents provided below, forexample, allow an understanding of previous attempts.

The technological document “A Highly time sensitive XOR gate for probeattempt detectors” (S. Manich, et al., IEEE Trans. Circuits Syst., II:Exp. Briefs, vol. 60, no. 11, pp. 786-790, November 2013) presents atechnique of detecting a probing capacitance delay, which occurs when asemiconductor chip is depackaged and the data bus within is probed.

SUMMARY OF THE INVENTION

An aspect of the invention is to provide a secure semiconductor chip andan operating method therefor, where the secure semiconductor chip candetect physical attacks and perform a countermeasure when an attack isdetected.

One aspect of the invention provides a semiconductor chip that includes:at least one data bus, which is configured to transmit data processed bythe semiconductor chip; an electric potential generator block, which ispackaged together with the at least one data bus to be blocked fromexternal light by a package, and which is configured to detect an eventof the package being unable to block the external light; and a switch,which is configured to cut off the transmission of at least some data inthe at least one data bus if such an event is detected.

In an embodiment of the invention, the electric potential generatorblock may include an energy harvesting element that generates energy byusing the light when exposed to the external light.

In an embodiment of the invention, the electric potential generatorblock may include: at least one photodiode configured to generate acurrent when exposed to the external light; a capacitor configured tostore an electric charge caused by at least a portion of the current;and a pull-down resistor configured to discharge the electric chargefrom the capacitor.

In an embodiment of the invention, the switch may be turned on by apotential difference occurring at both ends of the pull-down resistor,during a discharge of the electric charge by way of the pull-downresistor, to discharge at least some data from the at least one data busto the ground and thereby cut off the transmission.

In an embodiment of the invention, the pull-down resistor may include anactive element having a resistance value that is programmable by asetting.

In an embodiment of the invention, increasing a setting of the pull-downresistor may decrease the amount of discharged current required forturning on the switch such that the switch is turned on relativelyeasily, and decreasing a setting of the pull-down resistor may increasethe amount of discharged current required for turning on the switch suchthat the switch is turned on relatively difficultly.

In an embodiment of the invention, the at least one photodiode mayinclude a multiple number of photodiodes cascaded in at least a portionthereof.

In an embodiment of the invention, the at least one photodiode mayinclude a multiple number of photodiodes connected hierarchically in atree structure.

In an embodiment of the invention, the at least one data bus may includea multiple number of data buses configured to transmit data in parallel,and the multiple data buses may share the electric potential generatorblock.

Another aspect of the invention provides a protection device that is tobe embedded in a semiconductor chip packaging, where the protectiondevice includes: an electric potential generator block configured todetect an event in which the package is unable to block external light;and a switch configured to cut off at least a portion of datatransmission paths within the semiconductor chip if such an event isdetected.

In an embodiment of the invention, the electric potential generatorblock may include: at least one photodiode configured to generate acurrent when exposed to the external light; a capacitor configured tostore an electric charge caused by at least a portion of the current;and a pull-down resistor configured to discharge the electric chargefrom the capacitor.

In an embodiment of the invention, the switch may be turned on by apotential difference occurring at both ends of the pull-down resistor,during a discharge of the electric charge by way of the pull-downresistor, to ground at least a portion of the transmission paths andthereby cut off the transmission paths.

In an embodiment of the invention, the pull-down resistor may include anactive element having a resistance value that is programmable by asetting.

In an embodiment of the invention, increasing a setting of the pull-downresistor may decrease the amount of discharged current required forturning on the switch such that the switch is turned on relativelyeasily, and decreasing a setting of the pull-down resistor may increasethe amount of discharged current required for turning on the switch suchthat the switch is turned on relatively difficultly.

In an embodiment of the invention, the at least one photodiode mayinclude a multiple number of photodiodes connected hierarchically in atree structure.

Yet another aspect of the invention provides a method of detecting adamage to a packaging as performed by a semiconductor chip, where themethod includes: generating a potential difference at both ends of apull-down resistor when light infiltrates from outside the packaging ofthe semiconductor chip due to the damage to the packaging, thegenerating performed by an electric potential generator block embeddedin a form of an on-chip module; and cutting off data transmission bygrounding at least a portion of data transmission paths within thesemiconductor chip by way of the potential difference.

The present invention makes it possible to detect physical attacks andperform a countermeasure when an attack is detected.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram for describing a secure semiconductor chipaccording to an embodiment of the invention.

FIG. 2 is a diagram conceptually illustrating a portion of a securesemiconductor chip according to an embodiment of the invention.

FIG. 3 is an example diagram for describing the operation of a securesemiconductor chip according to an embodiment of the invention.

FIG. 4 is an example diagram for describing the operation of a securesemiconductor chip according to an embodiment of the invention.

FIG. 5 is a timing diagram for describing a method by which asemiconductor chip according to an embodiment of the invention maydetect damage to the packaging.

FIG. 6 is a diagram illustrating an example of an on-chip photodiode ofa security device in a semiconductor chip according to an embodiment ofthe invention.

FIG. 7 is a flow diagram illustrating a method by which a semiconductorchip according to an embodiment of the invention may detect damage tothe packaging.

DETAILED DESCRIPTION OF THE INVENTION

Certain embodiments of the invention will be described below in moredetail with reference to the accompanying drawings. However, the scopeof rights is not constrained by or limited to such embodiments. In thedrawings, the same reference numerals represent the same components.

While the terms used in the descriptions below are those that aretypically and commonly used in the relevant field of technology,different terms can be used under different circumstances due totechnological advances and/or changes, traditions, preferences oftechnicians, etc. Thus, the terms used in the descriptions below mustnot be understood to be limiting the technical spirit and are to beunderstood as illustrative terms.

Furthermore, in certain cases, some of the terms used were arbitrarilychosen by the applicant, and in such cases, the detailed meanings of theterms may be disclosed in the corresponding descriptions. Thus, theterms used in the descriptions below should be understood not only byhow the terms are named but by the meanings conveyed by the terms aswell as the context of the overall specification.

While such terms as “first” and “second”, etc., can be used to describevarious elements, such elements are to be interpreted only asdistinguishing one element from another. For example, a first elementcan be referred to as a second element, and similarly a second elementcan be referred to as a first element.

When an element is mentioned as being “connected” to another element, itshould be understood that the element can be directly connected orjoined to the other element but can also have yet another elementinterposed therebetween.

An expression used in the singular encompasses the expression of theplural, unless it has a clearly different meaning in the context. In thepresent specification, it is to be understood that terms such as“including” or “having”, etc., are intended to indicate the existence ofthe features, numbers, steps, actions, components, parts, orcombinations thereof disclosed in the specification and are not intendedto preclude the possibility that one or more other features, numbers,steps, actions, components, parts, or combinations thereof may exist ormay be added.

As mentioned above, various physical attacks and software attacks on asemiconductor chip can pose a threat to the security or stability of thesemiconductor chip. In particular, if the data bus within thesemiconductor chip is accessed via a depackaging of the semiconductorchip, data can be exposed to hacking, etc., and as such, it is desirableto provide a structure that can fundamentally block the leakage of datain such cases.

Generally, when depackaging occurs, light from outside the packaging ofthe semiconductor chip infiltrates the inside of the packaging. Althoughit is possible that the depackaging itself does not cause light to enterin special cases, for example when the depackaging occurs under limitedcircumstances such as in a darkroom, etc., there would still be photonsdetected during the process of accessing the data bus or observing thestructure inside the chip.

Thus, a structure is proposed that uses a photosensitive element todetect, and if necessary counter, an anomaly under circumstances inwhich light infiltrates the interior of the semiconductor chip due tothe occurrence of a depackaging attack or some other abnormal situation.For example, the semiconductor chip may include an energy harvestingelement within the package. In one example, the energy harvestingelement can include an on-chip photodiode. Since a depackaging attackwould cause the photodiode to generate a voltage, it would be possibleto detect light infiltrating the interior of the packaging. As an energyharvesting technique is used, it is still possible for the energyharvester to accumulate light energy from the ambient light and operatea protection trigger signal if the package is removed or damaged, evenwhen there is no power supplied to the chip. A more detailed descriptionof various embodiments is provided below with reference to the drawings.

FIG. 1 is a block diagram for describing a secure semiconductor chipaccording to an embodiment of the invention. In an embodiment of theinvention, a secure semiconductor chip 100 can include an electricpotential generator block 110, a switch 120, and a data bus 130. Thesecure semiconductor chip 100 can detect an anomaly such as adepackaging attack, etc., by a method of collecting light energy asdescribed above.

In an embodiment of the invention, the electric potential generatorblock 110 can employ a structure for collecting light energy to beconfigured to create a potential difference when light energy greaterthan or equal to a particular amount is collected. For example, theelectric potential generator block 110 can collect light energy that haspenetrated into the interior of the packaging by using an energyharvesting element or a photodiode, etc., and use at least a portion ofthe collected light energy to create a potential difference by way of acapacitor and a pull-down resistor.

More specifically, the electric potential generator block 110 caninclude at least one photodiode that generates an electric current whenexposed to external light, a capacitor that stores an electric chargeresulting from at least a portion of the current, and a pull-downresistor that causes the electric charge to be discharged from thecapacitor.

In an embodiment of the invention, the switch 120 can cut off the dataoutput of the data bus 130 of the semiconductor chip by using thepotential difference generated by the capacitor and the pull-downresistor. For example, the switch 120 can be turned off, if there is nolight energy collected, to enable the data output of the data bus 130 toproceed as normal, but if an anomaly such as a depackaging, etc., isdetected by way of the light energy collected by the electric potentialgenerator block 110, the switch 120 can cut off the data output of thedata bus 130 so that the data output does not proceed as normal.

According to an embodiment of the invention, in cases where the securesemiconductor chip 100 includes a multiple number of data buses 130, thesetup can be configured such that one electric potential generator block110 is shared by multiple data buses 130. For example, a structure canbe selected in which the electric potential generator block 110 isconnected to a multiple number of switches 120 that correspondrespectively to a multiple number of data buses 130.

FIG. 2 is a diagram conceptually illustrating a portion of a securesemiconductor chip according to an embodiment of the invention. In anembodiment of the invention, the secure semiconductor chip can includean electric potential generator block 210, a switch 220, and data buses230.

In an embodiment of the invention, the electric potential generatorblock 210 can include a photodiode 211, a capacitor 212, and a pull-downresistor 213. For example, if the photodiode 211 is exposed to externallight and generates a current, an electric charge may be stored in thecapacitor 212 using the generated current. When the voltage of the uppernode of the capacitor 212 is raised by the storage of the electriccharge, a discharge current may be generated by the pull-down resistor213 from the voltage difference between the upper node of the capacitor212 and the ground.

Here, if the voltage at the upper node of the capacitor 212 increases toor above a threshold voltage, it can be determined that an anomaly suchas depackaging, etc., has occurred in the semiconductor chip, and aprotection circuit for the semiconductor chip can be operated by way ofthe switch 220, etc. For example, if the current generated at thephotodiode 211 is greater than the current discharged through thepull-down resistor 213, the voltage at the upper node of the capacitor212 would gradually increase, and when the voltage at the upper node ofthe capacitor 212 becomes greater than or equal to the thresholdvoltage, the protective countermeasure for the semiconductor chip can beperformed.

In the embodiment presented here, an example of a protectivecountermeasure for the semiconductor chip is disclosed, where the switch220 may cut off the data output of the data buses 230 to prevent anormal data output. If the voltage at the upper node of the capacitor212 is increased such that the switch 220 is turned on, then, forexample, the output of a second inverter (inv2) can be forcibly madelow, so that the output of the data buses 230 may all be low. By cuttingoff the PAD output of the internal data in this manner such that thedata input 240 of the data buses 230 is not transferred to the dataoutput 250, it is possible to prevent the data output from being leakedby an external attack.

However, cutting off the data transmission path as described above ismerely one of various embodiments for a countermeasure that can beperformed in the event of the package being removed or damaged, andthere can be other examples for countermeasures involving a protectioncircuit employing light energy harvesting to alter the electrical stateof the circuits from before a package removal or damage is incurred onthe semiconductor chip. For instance, other embodiments for a protectivecountermeasure for the semiconductor chip can entail erasing data,scrambling data, destroying or deactivating the semiconductor chip, etc.Thus, the countermeasures are not be interpreted as being limited to theexamples explicitly described herein.

If the potential difference, created by the current generated at thephotodiode 211 flowing through the pull-down resistor 213, is smallerthan a threshold of a particular level (where the threshold can beassociated with the turn-on threshold of a transistor switch), theprotective circuit may not operate. If the electric charge generated bythe energy harvesting is so small as to be unable to create a sufficientpotential difference at both ends of the capacitor 212, then it can bedetermined that an anomaly such as depackaging, etc., has not occurredin the semiconductor chip, and as such, the protective circuit may notbe operated. This operational threshold is associated with thesensitivity of the circuit as regards how sensitive the circuit is intriggering the protective countermeasure. The sensitivity can be setappropriately to prevent the protective circuit from being triggeredunnecessarily, such as by a dark current, which can occur temporarilyduring a normal course of operation of the semiconductor chip, or by Xrays, etc., which radiate from outside the semiconductor packaging andpenetrate through the package.

In an embodiment of the invention, the pull-down resistor 213 may beconfigured to be capable of adjusting the point at which the protectivecircuit begins to operate according to the intensity of the lightsensed. For example, if the resistance value of the pull-down resistor213 is increased, then the discharge current would decrease, andtherefore the cutting off of data output by the switch 220 can beperformed even though the current generated at the photodiode 211 isrelatively small. Conversely, if the resistance value of the pull-downresistor 213 is decreased, then the discharge current would increase,and therefore the cutting off of data output by the switch 220 can beperformed when the current generated at the photodiode 211 is relativelylarge.

That is, by implementing the pull-down resistor 213 as a programmablecomponent to control the magnitude of the discharge current, it ispossible to adjust the magnitude of the generated current at which theprotective circuit begins to operate. The size of the resistance valueof the pull-down resistor 213 can be designed to be an appropriate valuebased on the properties of the semiconductor chip, the type ofpackaging, the environment in which the semiconductor chip is used,etc., and can be implemented to be programmable.

According to an embodiment of the invention, in cases where the securesemiconductor chip includes a multiple number of data buses 230, thesetup can be configured such that one electric potential generator block210 is shared by multiple data buses 230. For example, a structure canbe selected in which the electric potential generator block 210 isconnected to a multiple number of switches 220 that correspondrespectively to a multiple number of data buses 230.

FIG. 3 is an example diagram for describing the operation of a securesemiconductor chip according to an embodiment of the invention. Thesecure semiconductor chip in FIG. 3 can, for example, be a part of thesecure semiconductor chip illustrated in FIG. 2. In an embodiment of theinvention, the secure semiconductor chip can include a photodiode 311, acapacitor 312, a pull-down resistor 313, a switch 320, and a data bus330.

FIG. 3 illustrates an example of the operation of the securesemiconductor chip before the occurrence of a security attack such asdepackaging, etc. In a normal environment where the packaging has notbeen damaged, both ends of the photodiode 311 may be in a statesubstantially the same as being open, so that the voltage at the uppernode of the capacitor 312 may be kept at a value close to the ground. Asdescribed above, even if a small current occurs temporarily, thedischarging structure using the pull-down resistor 313 can keep thevoltage of the upper node of the capacitor 312 at a value close to theground.

That is, the setup may be designed such that, before a security attacksuch as depackaging occurs, the current generated at the photodiode 211is smaller than the current discharged by way of the pull-down resistor213, with the result that the voltage of the upper node of the capacitor312 and the gate terminal of the switch 320 may be kept at a value closeto the ground.

Consequently, since the switch 320 may be kept in an off state, thepulse train provided at the data input 340 of the data bus 330 can betransferred as normal to the PAD data output 350 of internal data.

FIG. 4 is an example diagram for describing the operation of a securesemiconductor chip according to an embodiment of the invention. Thesecure semiconductor chip in FIG. 4 can, for example, be a part of thesecure semiconductor chip illustrated in FIG. 2. In an embodiment of theinvention, the secure semiconductor chip can include a photodiode 311, acapacitor 312, a pull-down resistor 313, a switch 320, and a data bus330, in the same arrangement as that described for FIG. 3.

FIG. 4 illustrates an example of the operation of the securesemiconductor chip after the occurrence of a security attack such asdepackaging, etc. In an environment where the packaging has been damagedand light has infiltrated into the interior of the packaging, thephotodiode 311 is able to sense the light energy, and the currentgenerated by the photodiode 311 may cause the voltage at the upper nodeof the capacitor 312 to gradually increase.

That is, the setup may be designed such that, if a security attack suchas depackaging has occurred, the current generated at the photodiode 211is greater than the current discharged by way of the pull-down resistor213, with the result that the voltage of the upper node of the capacitor312 and the gate terminal of the switch 320 may be gradually increased.

When the voltage of the upper node of the capacitor 312 and the gateterminal of the switch 320 becomes greater than or equal to a thresholdvoltage, it can be determined that an anomaly such as a depackaging,etc., has occurred in the semiconductor chip, and the data output of thedata bus 330 can be cut off by way of the switch 320 such that the dataoutput does not proceed as normal. That is, if the switch 320 is turnedon, then, for example, the output of the second inverter (inv2) can beforcibly made low, so that the output of the data bus 330 may all below. By cutting off the PAD output of the internal data in this mannersuch that the data input 440 of the data bus 330 is not transferred tothe data output 450, it is possible to prevent the data output frombeing leaked by an external attack.

FIG. 5 is a timing diagram for describing a method by which asemiconductor chip according to an embodiment of the invention maydetect damage to the packaging.

As an example, the PAD outputs (PAD0, PAD1, PAD2, PAD3) of four databuses are illustrated. V_(PD) represents the voltage formed at the uppernode of the capacitor using the current generated by the photodiode, andCLK represents a clock signal.

Looking at the trend of V_(PD) in the example illustrated in FIG. 5,V_(PD) begins to rise at a first point 510, which is when the photodiodebegins to generate a current due to a depackaging attack, and thevoltage continues to rise for a period of time until the rise in V_(PD)stops at a second point 520, which is when the current generated at thephotodiode becomes equal to the current discharged by way of thepull-down resistor.

Here, the threshold voltage can be selected as the difference betweenthe V_(PD) value for the first point 510 and the V_(PD) value for thesecond point 520. That is, the switch for cutting off the output of thedata bus can be made to turn on based on the threshold voltage. When thecutoff switch is turned on, the output of the data buses can all beforcibly made low, as already described above. In the illustratedexample, it can be seen that, due to the operation of the cutoff switch,the PAD outputs (PAD0, PAD1, PAD2, PAD3) of the four data buses do notoutput normal data but output only a low signal from a particular pointonward. In this manner, the leakage of internal data can befundamentally blocked.

FIG. 6 is a diagram illustrating an example of an on-chip photodiode ofa security device in a semiconductor chip according to an embodiment ofthe invention. The on-chip photodiode of FIG. 6 can be used, forexample, in implementing the electric potential generator block 110 ofthe secure semiconductor chip 100 in FIG. 1.

As in the illustration, an on-chip photodiode according to an embodimentof the invention can include multiple photodiodes cascaded in a treestructure in order to readily generate a high voltage required foroperating the circuit. When light energy that has infiltrated into theinterior of the packaging is collected by way of this structure, atleast a portion of the collected light energy can be transferred to thecapacitor to generate a potential difference. Adopting an on-chipphotodiode having such a tree structure may provide the advantage thatthe voltage required for operating the circuit can be generated evenwithout a DC-DC converter.

The photodiode can be substituted by or be used in conjunction with anarbitrary element capable of performing the same or a similar function.Also, in addition to the structure explicitly illustrated in FIG. 6,other structures that adapt or modify the structure can be used asappropriate for the corresponding embodiment.

As described above, when the current generated at the on-chip photodiodeis greater than the current discharged by way of the pull-down resistor,the voltage may increase at the upper node of the capacitor, causing thecutoff switch to be turned on. Therefore, the photosensitivityperformance and specific design of the on-chip photodiode can beoptimized in consideration of the properties of the pull-down resistorand the cutoff switch.

FIG. 7 is a flow diagram illustrating a method by which a semiconductorchip according to an embodiment of the invention may detect damage tothe packaging. For example, the method of FIG. 7 can be practiced as amethod of operating the secure semiconductor chip 100 of FIG. 1.

In step 710, light can enter from outside the packaging of thesemiconductor. Since such infiltration of light means that the packagingof the semiconductor chip has been damaged by a depackaging attack orsome other abnormal circumstance, it is desirable to perform acountermeasure to fundamentally block hacking attempts, etc., which mayoccur after a depackaging of the semiconductor chip.

As mentioned above, although it is possible that the depackaging itselfdoes not cause light to enter, for example when the depackaging occursunder limited circumstances such as in a darkroom, there would still bephotons detected during the process of accessing the data bus orobserving the internal structure of the chip.

In step 720, an electric potential generator block can be used togenerate a potential difference at both ends of a pull-down resistor.That is, since it has been determined from the infiltration of light instep 710 that a security attack such as depackaging, etc., has occurred,the electric potential generator block can generate a potentialdifference for activating the protective circuit.

For example, the setup can be designed such that the current generatedat the photodiode is greater than the current discharged by way of thepull-down resistor, with the result that the voltage at the upper nodeof the capacitor and the gate terminal of the cutoff switch maygradually increase.

In step 730, the potential difference can be used to cut off the datatransmission path within the semiconductor chip. For example, the PADoutput of each data bus can be forcibly made low, so that normal dataoutputs may not be transferred. Also, another protective measure for thesemiconductor chip, such as erasing data, scrambling data, or destroyingor deactivating the semiconductor chip, can be applied as necessaryeither additionally or alternatively. As mentioned above, while certainembodiments have been described herein with mention of cutting off thedata output of the data bus in relation to a method of operating aprotective circuit, it is to be appreciated that the protective measuresfor the semiconductor chip are not limited only to the examplesexplicitly described herein.

According to the embodiments described above, if the package of a chipis damaged or removed, an energy harvesting element such as aphotodiode, for example, may harvest the ambient light energy to operatea trigger circuit for initializing or erasing security data, etc. Theilluminance in a typical indoor space and the reactivity to light of theP-N junction of a CMOS are 0.5 W/m² and 0.5 A·cm⁻²/W·cm⁻², respectively.Assuming an example environment, a photodiode having an area of 100 um²can generate a photoelectric current of 2.5 nA. Supposing a capacitor of10 pF with a supply voltage of 1.8V, the time required for operating theprotective circuit is approximately 72 ms. When the capacitor is fullycharged, a current of 18 uA is supplied for 10 us to report to thetrigger circuit. With such harvesting of light energy, it is possible toperform a protective operation such as deleting the content of the SRAMin a very short amount of time (for instance, less than 0.1 seconds).Thus, physical attacks such as removing at least a portion of thepackage or invasive micro-probing can be effectively deterred by theembodiments described above.

The device described above can be implemented as one or more hardwarecomponents for a memory, one or more software components for controllingthe memory, and/or one or more combinations of hardware components andsoftware components. For example, the device and components in theembodiments described above can be implemented by using one or moregeneral purpose computer or special purpose computer, which may include,for example, a processor, a controller, an ALU (arithmetic logic unit),a digital signal processor, a microcomputer, a FPA (field programmablearray), a PLU (programmable logic unit), a microprocessor, or any otherdevice capable of executing and responding to instructions.

The software can include a computer program, code, instructions, or acombination of one or more of the above to configure a processing deviceto operate as desired or command a processing device independently orcollectively. The software and/or data can be permanently or temporarilyembodied as a type of machinery, component, physical device, virtualequipment, computer storage medium or device, or transmitted signal waveto be interpreted by a processing device or to provide instructions ordata to a processing device. The software can also be distributed overcomputer systems connected over a network and can be stored or executedin a distributed manner. The software and data can be stored on one ormore computer-readable recorded medium.

A method of controlling memory operation according to an embodiment ofthe invention can be implemented in the form of program instructionsthat may be performed using various computer means and can be recordedin a computer-readable medium. Such a computer-readable medium caninclude program instructions, data files, data structures, etc., aloneor in combination. The program instructions recorded on the medium canbe designed and configured specifically for the embodiment or can be atype known to and used by the skilled person in the field of computersoftware. A computer-readable medium may include a hardware device thatis specially configured to store and execute program instructions. Someexamples may include magnetic media such as hard disks, floppy disks,and magnetic tapes, optical media such as CD-ROM's and DVD's,magneto-optical media such as floptical disks, and hardware devices suchas ROM, RAM, flash memory, etc. Examples of the program of instructionsmay include not only machine language codes produced by a compiler butalso high-level language codes that can be executed by a computerthrough the use of an interpreter, etc. The hardware mentioned above canbe made to operate as one or more software modules that perform theactions of the embodiments, and vice versa.

While the embodiments of the invention are described above withreference to a limited number of drawings, a person having ordinaryskill in the relevant field of technology would be able to derivevarious modifications and alterations from the disclosure providedabove. A satisfactory result may be achieved, for example, by performingthe procedures described above in an order different from that of amethod described above and/or by coupling or combining components of theabove-mentioned systems, structures, devices, circuits, etc., in a formdifferent from that described above or replacing or substituting certaincomponents with other components or equivalents. Therefore, otherimplementations, other embodiments, and equivalents of the claims setforth below are encompassed within the scope of claims.

What is claimed is:
 1. A semiconductor chip comprising: at least onedata bus configured to transmit data processed by the semiconductorchip; an electric potential generator block packaged together with theat least one data bus to be blocked from external light by a package,the electric potential generator block configured to detect an event inwhich the package is unable to block the external light; and a switchconfigured to block a transmission of at least some data in the at leastone data bus if the event is detected.
 2. The semiconductor chip ofclaim 1, wherein the electric potential generator block comprises anenergy harvesting element configured to generate energy by using thelight when exposed to the external light.
 3. The semiconductor chip ofclaim 1, wherein the electric potential generator block comprises: atleast one photodiode configured to generate a current when exposed tothe external light; a capacitor configured to store an electric chargecaused by at least a portion of the current; and a pull-down resistorconfigured to discharge the electric charge from the capacitor.
 4. Thesemiconductor chip of claim 3, wherein the switch is turned on todischarge at least some data from the at least one data bus to theground and thereby block the transmission, the switch turned on by apotential difference occurring at both ends of the pull-down resistorduring a discharge of the electric charge by way of the pull-downresistor.
 5. The semiconductor chip of claim 4, wherein the pull-downresistor is an active element having a resistance value, the resistancevalue programmable by a setting.
 6. The semiconductor chip of claim 5,wherein increasing a setting of the pull-down resistor decreases anamount of discharged current required for turning on the switch suchthat the switch is turned on relatively easily, and decreasing a settingof the pull-down resistor increases an amount of discharged currentrequired for turning on the switch such that the switch is turned onrelatively difficultly.
 7. The semiconductor chip of claim 3, whereinthe at least one photodiode includes a plurality of photodiodes cascadedin at least a portion thereof.
 8. The semiconductor chip of claim 3,wherein the at least one photodiode includes a plurality of photodiodesconnected hierarchically in a tree structure.
 9. The semiconductor chipof claim 1, wherein the at least one data bus includes a plurality ofdata buses configured to transmit data in parallel, and the plurality ofdata buses share the electric potential generator block.
 10. Aprotection device embedded in a semiconductor chip packaging, theprotection device comprising: an electric potential generator blockconfigured to detect an event in which the package is unable to blockexternal light; and a switch configured to block at least a portion ofdata transmission paths within the semiconductor chip if the event isdetected.
 11. The protection device of claim 10, wherein the electricpotential generator block comprises: at least one photodiode configuredto generate a current when exposed to the external light; a capacitorconfigured to store an electric charge caused by at least a portion ofthe current; and a pull-down resistor configured to discharge theelectric charge from the capacitor.
 12. The protection device of claim11, wherein the switch is turned on to ground at least a portion of thetransmission paths and thereby block the transmission paths, the switchturned on by a potential difference occurring at both ends of thepull-down resistor during a discharge of the electric charge by way ofthe pull-down resistor.
 13. The protection device of claim 12, whereinthe pull-down resistor is an active element having a resistance value,the resistance value programmable by a setting.
 14. The protectiondevice of claim 13, wherein increasing a setting of the pull-downresistor decreases an amount of discharged current required for turningon the switch such that the switch is turned on relatively easily, anddecreasing a setting of the pull-down resistor increases an amount ofdischarged current required for turning on the switch such that theswitch is turned on relatively difficultly.
 15. The protection device ofclaim 11, wherein the at least one photodiode includes a plurality ofphotodiodes connected hierarchically in a tree structure.
 16. A methodof detecting a damage to a packaging, the method performed by asemiconductor chip, the method comprising: generating a potentialdifference at both ends of a pull-down resistor when light infiltratesfrom outside a packaging of the semiconductor chip due to the damage tothe packaging, the generating performed by an electic potentialgenerator block embedded in a form of an on-chip module; and blockingdata transmission by grounding at least a portion of data transmissionpaths within the semiconductor chip by way of the potential difference.